The present invention generally relates to communication systems, and more particularly to a communication system employing a multi-conjunction architecture.
A multi-channel lattice communication network applicable to local area networks (LANs), public line networks and especially to a multi-media communication was previously proposed in a U.S. patent application Ser. No. 096,532 filed Sept. 15, 1987 in which the assignee is the same as the assignee of the present application. The proposed lattice communication network is analogous to nerve cells of a living body, and employs node apparatuses. Each node apparatus has a plurality of input and output channels and is used as a communication control element. Such node apparatuses are coupled in a multi-conjunction to constitute the lattice communication network. Each node apparatus transfers one of incoming digital signals according to a first-come-first-served logic (hereinafter simply referred to as a first-come-first-output logic).
The proposed lattice communication network has a large degree of freedom of network topology because of the multi-conjunction architecture. Thus, the survivability of data is high. In other words, even when a fault occurs in a path of the communication network, it is possible to carry out the communication through other paths. Furthermore, it is possible to select optimum paths for the communication because each node apparatus transfers the incoming digital signals according to the first-come-first-output logic.
On the other hand, the proposed lattice communication network employs a multi-channel system in which a plurality of connecting channels are established, so as to effectively achieve a full duplex communication. The proposed lattice communication network is effectively applicable to the physical layer to the network layer of the open system interconnection (OSI), for example.
In order to obtain a high data survivability in the lattice communication network, it is important that the effects of faults are minimized and the trouble shooting is carried out quickly. There are three major faults, namely, a first fault caused by the fault in the node apparatus itself, a second fault in the sending path, and a third fault in a receiving path. In the proposed lattice communication network, a probability that the communication will be interfered by the first through third faults is extremely small.
The proposed lattice communication network is capable of detecting a fault in a node apparatus or a terminal device which receives a signal from a predetermined node apparatus. However, in cases where a signal is broadcasted to a destination address which does not exist in the communication network or a fault occurs in a terminal device or a node apparatus in the communication network, the broadcasting of the signal to all of the node apparatuses within the communication network is continued. As a result, there are problems in that a new communication is interfered by the unnecessary continuation of the broadcasting and a set link (fixed communication path) cannot be cancelled.